ABSTRACT
Neuroimaging of dementia of the Alzheimer type (DAT) has progressed rapidly during the last 7 years. Contributions of positron emission tomography (PET) originates in the early observation of Kuhl et al that demonstrated that in Alzheimer type dementia there is a bilateral temporoparietal depressed utilization of fluorodeoxyglucose. This pattern has been confirmed by several investigators and has been observed also with Regional cerebral blood flow (rCBF) measurement of cortical perfusion by the single-photon emission computed tomography (SPECT) technique. SPECT offers the possibility of incorporation of the PET findings to many university centers lacking PET and to community hospital level. rCBF measurements can be accomplished based on the Fick principle that states that a substance is transported to a tissue by arterial blood less the amount carried away by venous blood. Imaging of a dynamic process with SPECT can be achieved with a system originally developed by Kuhl, a very sensitive device that gathers sequential tomographic images.
